Bomar Commercial Grade Cast Aluminum Hatch 12 inch x 18 inch Oval 4-Dog Flush Mount Watertight. Hatch is made of Almag-35 Aluminum and has an outside opening stainless steel t-handle. This hatch is not hinged. Hatch Opening: 12-3/16 inches x 18-1/4 inches (310 x 464 millimeters), Outside Deck Flange: 18-11/16 inches x 24-3/4 inches (475 x 629 millimeters), Cutout: 14-15/16 inches x 21 inches (380 millimeters x 534 millimeters), Extends below deck: 5-3/8 inches (143 millimeters), Weight: 27 pounds. This hatch does not open from the inside. An optional inside handle is available.